Processes for preparing a diaminopyrimidine derivative or acid addition salt thereof

ABSTRACT

Provided are a novel process for preparing a diaminopyrimidine derivative or acid addition salt thereof having an activity as a 5-HT 4  receptor agonist, crystalline forms of a hydrochloride of the diaminopyrimidine derivative, and processes for preparing the same.

TECHNICAL FIELD

The present invention relates to a novel process for preparing adiaminopyrimidine derivative or acid addition salt thereof having anactivity as a 5-HT₄ receptor agonist. And also, the present inventionrelates to novel crystalline forms of a hydrochloride of thediaminopyrimidine derivative and processes for preparing the same.

BACKGROUND ART

The diaminopyrimidine derivative of Formula 1 below has a chemical nameof(S)—N-(1-(2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl)pyrrolidin-3-yl)acetamide.The diaminopyrimidine derivative of Formula 1 or pharmaceuticallyacceptable salt thereof (e.g., hydrochloride) functions as a 5-HT₄receptor agonist, and therefore can be usefully applied for preventingor treating dysfunction in gastrointestinal motility, one of thegastrointestinal diseases, such as gastroesophageal reflux disease(GERD), constipation, irritable bowel syndrome (IBS), dyspepsia,post-operative ileus, delayed gastric emptying, gastroparesis,intestinal pseudo-obstruction, drug-induced delayed transit, or diabeticgastric atony (WO 2012/115480).

A process for preparing the compound of Formula 1 has been disclosed inWO 2012/115480. Specifically, as shown in the following Reaction Scheme1, the process for preparing the compound of Formula 1 orpharmaceutically acceptable salt thereof comprises reacting a compoundof Formula (I) with POCl₃ to prepare a compound of Formula (II);reacting the compound of Formula (II) with a compound of Formula (III)under the presence of a base to prepare a compound of Formula (IV);reacting the compound of Formula (IV) with a compound of Formula (V) toprepare the compound of Formula 1; and optionally converting thecompound of Formula 1 to a pharmaceutically acceptable salt thereof.

In the process of the Reaction Scheme 1, the compound of Formula (II) isprepared through performing the reaction with an excess POCl₃ at a hightemperature of 100° C. or higher, thereby producing impurities in highlevel. Therefore, in order to remove the impurities, said reactionrequires performing the purification step using a column chromatographythat is unsuitable for industrial mass production. And also, thecompound of Formula (II) is obtained in the form of oil; and is readilydecomposed at room temperature, thereby bring about stability problems,i.e., low stability.

Especially, since the compound of Formula (II) has two reactive sites(i.e., the 2 and 4 positions of the pyrimidine ring), the structuralisomeric impurity that the compound of Formula (III) has been bound tothe 2 position of the pyrimidine ring is produced in significant level.Therefore, the reaction of the compound of Formula (II) and the compoundof Formula (III) shows very low yield of about 55˜60%; and causes theproblem that the structural isomeric impurity resides in the finalproduct (i.e., the compound of Formula 1).

And also, in the reaction of the compound of Formula (IV) and thecompound of Formula (V), the compound of Formula (V) is known as amaterial having genetic toxicity. Therefore, in order to avoid theresidence of the compound of Formula (V) in the final product (i.e., thecompound of Formula 1), there is a problem that the purification stepusing a column chromatography that is unsuitable for industrial massproduction should be carried out.

In addition, WO 2012/115480 has disclosed the step for converting thecompound of Formula 1 to a hydrochloride thereof. The converting stepcomprises reacting the compound of Formula 1 with hydrochloric acid inethyl acetate, stirring at room temperature for 1 hour, and thenfiltering the product. It has been found by the present inventors thatthe hydrochloride of the compound of Formula 1 obtained by said methodis in the amorphous form and brings about the problem producingdeacetylated impurities in high level when stored at room temperature.

DISCLOSURE Technical Problem

The present inventors carried out various researches in order to developa novel process capable of solving the problems of the prior art methodsfor preparing the compound of Formula 1 or acid addition salt.Especially, the present inventors carried out various researches inorder to develop a novel process for avoiding the use of the compound ofFormula (II), i.e., the intermediate that is unstable, difficult tohandle, and causes formation of the structural isomeric impurity. As theresults thereof, the present inventors has developed a novel processwhich comprises forming a pyrimidine ring from a substitutedphenylguanidine derivative or its salt, activating the pyrimidine ringto prepare a novel intermediate, and reacting the novel intermediatewith (S)-3-acetamidopyrrolidine. It has been found that said process cansolve the problems of the prior art methods and is suitable forindustrial mass production.

And also, the present inventors have isolated novel crystalline forms ofa hydrochloride of the compound of Formula 1; and found that saidcrystalline forms exhibit remarkably excellent stability, in comparisonwith the amorphous form according to the prior art.

Therefore, it is an object of the present invention to provide a processfor preparing a diaminopyrimidine derivative or acid addition saltthereof, the process comprising the use of a novel intermediate.

And also, it is another object of the present invention to provide thenovel intermediate and processes for preparing the same.

And also, it is still another object of the present invention to providecrystalline forms of a hydrochloride of the compound of Formula 1 andprocesses for preparing the same.

Technical Solution

In accordance with an aspect of the present invention, there is provideda process for preparing a compound of Formula 1 or acid addition saltthereof, comprising (a) reacting a compound of Formula 2 or salt thereofwith (S)-3-acetamidopyrrolidine to prepare a compound of Formula 1; andoptionally (b) reacting the compound of Formula 1 with an acid toprepare an acid addition salt of the compound of Formula 1:

wherein, R¹ is a C₁˜C₃ alkyl group; or a phenyl group optionallysubstituted with one or more substituents selected from the groupconsisting of halogen, C₁˜C₃ alkyl, and cyano.

In accordance with another aspect of the present invention, there isprovided a compound of Formula 2 or salt thereof:

wherein, R¹ is the same as defined in the above.

In accordance with still another aspect of the present invention, thereis provided a process for preparing a compound of Formula 2 or saltthereof comprising (i) reacting a compound of Formula 5 or salt thereofwith methyl 3-oxohexanoate to prepare a compound of Formula 4; (ii)reacting the compound of Formula 4 with R¹-sulfonyl halide to prepare acompound of Formula 2; and optionally (iii) converting the compound ofFormula 2 to a salt thereof:

In accordance with still another aspect of the present invention, thereis provided a crystalline form A of a hydrochloride of the compound ofFormula 1, having an XRPD pattern with peaks at 7.4, 9.1, 12.0, 12.5,13.5, 14.1, 15.9, 16.8, 18.3, 19.1, 24.6, 25.3 and 26.8° 2θ±0.2° 2θ.

In accordance with still another aspect of the present invention, thereis provided a process for preparing the crystalline form A of ahydrochloride of the compound of Formula 1, the process comprising (p)refluxing a reaction mixture obtained by adding hydrochloric acid to acompound of Formula 1 in an organic solvent; (q) cooling the reactionmixture obtained from Step (p) to form a precipitate; and (r) isolatingthe precipitate of Step (q).

In accordance with still another aspect of the present invention, thereis provided a crystalline form B of a hydrochloride of the compound ofFormula 1, having an XRPD pattern with peaks at 7.3, 8.8, 11.8, 12.5,13.2, 13.6, 14.5, 17.7, 18.6, 19.6, 22.0, 24.9, 25.2, and 25.9° 2θ±0.2°2θ.

In accordance with still another aspect of the present invention, thereis provided a process for preparing the crystalline form B of ahydrochloride of the compound of Formula 1, the process comprisingexposing the crystalline form A of a hydrochloride of the compound ofFormula 1 to a 40% or more relative humidity condition so as to controlthe water contents thereof to about 3.5% or more.

Advantageous Effects

The process of the present invention is carried out, by using a novelintermediate, i.e., the compound of Formula 2 or salt thereof, from asubstituted phenylguanidine derivative or its salt. Therefore, theprocess of the present invention can avoid the use of the compound ofFormula (II), i.e., the intermediate that is unstable, difficult tohandle, and causes formation of the structural isomeric impurity. Andalso, the process of the present invention can provide the compound ofFormula 1 or acid addition salt thereof in high yield and purity and besuitably applied to industrial mass production. In addition, the novelcrystalline forms of a hydrochloride of the compound of Formula 1, i.e.,the crystalline forms A and B, exhibit remarkably excellent stability,in comparison with the amorphous form according to the prior art.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows an XRPD spectrum of the crystalline form A of ahydrochloride of the compound of Formula 1.

FIG. 2 shows an XRPD spectrum of the crystalline form B of ahydrochloride of the compound of Formula 1.

BEST MODE

The present invention provides a process for preparing a compound ofFormula 1 or acid addition salt thereof, comprising (a) reacting acompound of Formula 2 or salt thereof with (S)-3-acetamidopyrrolidine toprepare a compound of Formula 1; and optionally (b) reacting thecompound of Formula 1 with an acid to prepare an acid addition salt ofthe compound of Formula 1:

wherein, R¹ is a C₁˜C₃ alkyl group; or a phenyl group optionallysubstituted with one or more substituents selected from the groupconsisting of halogen, C₁˜C₃ alkyl, and cyano.

In the process of the present invention, (S)-3-acetamidopyrrolidine, oneof the reactants, is a known compound and commercially available. Andalso, (S)-3-acetamidopyrrolidine may be formed by deprotecting theamino-protecting group from the commercially available compound ofFormula 3 below.

wherein, R² is a amino-protecting group such as t-butoxycarbonyl.

The deprotection may be carried out with one or more acids selected fromthe group consisting of hydrochloric acid, sulfuric acid, phosphoricacid, nitric acid, acetic acid, formic acid, sulfonic acid,p-toluenesulfonic acid, and methanesulfonic acid, preferably withp-toluenesulfonic acid or hydrochloric acid. The deprotection may becarried out in one or more solvents selected from the group consistingof dichloromethane, dichloroethane, N,N-dimethylformamide,dimethylacetamide, dimethyl sulfoxide, tetrahydrofuran, ethyl acetate,and toluene, preferably in toluene. And also, the deprotection may becarried out at the temperature ranging from 0° C. to 40° C., preferablyfrom 10° C. to 30° C.

In an embodiment, the deprotection and the reaction of the formed(S)-3-acetamidopyrrolidine with a compound of Formula 2 or salt thereofmay be carried out in a one-pot reaction. That is, in the process of thepresent invention, Step (a) may include (a1) deprotecting the compoundof Formula 3 to form (S)-3-acetamidopyrrolidine; and (a2) performing areaction through adding a compound of Formula 2 or salt thereof to thereaction mixture of Step (a1). The reaction of a compound of Formula 2or salt thereof with (S)-3-acetamidopyrrolidine may be carried out inthe presence of a base. The base may be one or more selected from thegroup consisting of potassium tert-butoxide, sodium hydroxide, potassiumhydroxide, sodium hydride, sodium carbonate, potassium carbonate,potassium phosphate (including potassium phosphate monobasic, potassiumphosphate dibasic, and potassium phosphate tribasic), sodium phosphate(including sodium phosphate monobasic, sodium phosphate dibasic, andsodium phosphate tribasic), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU),1,4-diazabicyclo[2.2.2]octane (DABCO), 1,5-diazabicyclo[4.3.0]non-5-ene(DBN), pyridine, triethylamine, diisopropylamine, anddiisopropylethylamine. Preferably, the base may be triethylamine ordiisopropylethylamine. More preferably, the base may bediisopropylethylamine. The reaction of a compound of Formula 2 or saltthereof with (S)-3-acetamidopyrrolidine may be carried out at thetemperature ranging from 40° C. to 130° C., preferably from 80° C. to90° C.

In the process of the present invention, the acid used in Step (b) maybe a conventional inorganic or organic acid suitable for forming adesired acid addition salt. Preferably, the acid used in Step (b) may behydrochloric acid. When hydrochloric acid is used in Step (b), theproduct is obtained in the form of a hydrochloride of the compound ofFormula 1.

In the process of the present invention, the compound of Formula 2 orsalt thereof may be prepared or formed by a process comprising (i)reacting a compound of Formula 5 or salt thereof with methyl3-oxohexanoate to prepare a compound of Formula 4; (ii) reacting thecompound of Formula 4 with R¹-sulfonyl halide to prepare a compound ofFormula 2; and optionally (iii) converting the compound of Formula 2 toa salt thereof:

In the reaction of Step (i), the compound of Formula 5 may be preparedby reacting 4-amino-2-nitroaniline with cyanamide under an acidiccondition, according to known methods, e.g., U.S. Pat. No. 6,562,854 B2and so on. The salt of the compound of Formula 5 may in the form of1-(4-amino-3-nitrophenyl)guanidine hemicarbonate. The reaction of Step(i), i.e., cyclization reaction, may be carried out in C₁˜C₅ alcohol,preferably in n-butanol. And also, said cyclization reaction may becarried out at the temperature ranging from 50° C. to 130° C.,preferably from 90° C. to 120° C.

The reaction of Step (ii), i.e., the reaction of the compound of Formula4 and R¹-sulfonyl halide, may be carried out in the presence of a base.The base may be one or more selected from the group consisting ofpotassium tert-butoxide, sodium hydroxide, potassium hydroxide, sodiumhydride, sodium carbonate, potassium carbonate, potassium phosphate(including potassium phosphate monobasic, potassium phosphate dibasic,and potassium phosphate tribasic), sodium phosphate (including sodiumphosphate monobasic, sodium phosphate dibasic, and sodium phosphatetribasic), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU),1,4-diazabicyclo[2.2.2]octane (DABCO), 1,5-diazabicyclo[4.3.0]non-5-ene(DBN), pyridine, triethylamine, diisopropylamine, anddiisopropylethylamine. Preferably, the base may be triethylamine. Thereaction of the compound of Formula 4 with R¹-sulfonyl halide may becarried in the presence of or in the absence of a solvent. When thereaction is carried out in presence of a solvent, the solvent may be oneor more selected from the group consisting of acetone,methylethylketone, dichloromethane, dichloroethane,N,N-dimethylformamide, dimethylacetamide, dimethyl sulfoxide,tetrahydrofuran, C₁˜C₅ alcohol, ethyl acetate, and toluene. And also,the reaction of the compound of Formula 4 with R¹-sulfonyl halide may becarried at the temperature ranging from 0° C. to 60° C. If necessary,the compound of Formula 2 obtained from the reaction of the compound ofFormula 4 with R¹-sulfonyl halide may be additionally converted to asalt form thereof (e.g., to the form of an acid addition salt), byreacting with an acid such as hydrochloric acid, sulfuric acid,phosphoric acid, nitric acid, acetic acid, formic acid, or sulfonicacid. The obtained compound of Formula 2 or salt thereof may beisolated. And also, the obtained compound of Formula 2 or salt thereofmay be directly used in the subsequent reaction, i.e., in the reactionwith (S)-3-acetamidopyrrolidine, without the isolation thereof. In anembodiment, the reaction mixture of Step (ii) may be directly used inthe reaction of Step (a), without isolating the compound of Formula 2 orsalt thereof.

An example of the overall reaction steps of the present invention isshown in Reaction Scheme 2 below.

In the Reaction Scheme 2, R¹ is the same as defined in the above.

The present invention also provides a compound of Formula 2 or saltthereof useful for preparing the compound of Formula 1 or acid additionsalt thereof:

wherein, R¹ is the same as defined in the above.

The present invention also provides a process for preparing the compoundof Formula 2 or salt thereof. That is, the present invention provides aprocess for preparing the compound of Formula 2 or salt thereofcomprising (i) reacting a compound of Formula 5 or salt thereof withmethyl 3-oxohexanoate to prepare a compound of Formula 4; (ii) reactingthe compound of Formula 4 with R¹-sulfonyl halide to prepare a compoundof Formula 2; and optionally (iii) converting the compound of Formula 2to a salt thereof:

The reactions of Steps (i) and (ii) are as described in the above.

The present invention also provides novel crystalline forms of ahydrochloride of the compound of Formula 1 having excellent stability.

In an aspect, the present invention provides a crystalline form A of ahydrochloride of the compound of Formula 1, having an XRPD pattern withpeaks at 7.4, 9.1, 12.0, 12.5, 13.5, 14.1, 15.9, 16.8, 18.3, 19.1, 24.6,25.3 and 26.8° 2θ±0.2° 2θ.

Preferably, the crystalline form A of a hydrochloride of the compound ofFormula 1 may have the XRPD pattern of FIG. 1. And also, the crystallineform A of a hydrochloride of the compound of Formula 1 may have adifferential scanning calorimetry (DSC) thermogram showing anendothermic peak at between 229° C. and 235° C., preferably at 232±2° C.The onset temperature may be 230±2° C.

The present invention also includes, within its scope, a process forpreparing the crystalline form A of a hydrochloride of the compound ofFormula 1. Specifically, the present invention provides a process forpreparing the crystalline form A of a hydrochloride of the compound ofFormula 1, the process comprising (p) refluxing a reaction mixtureobtained by adding hydrochloric acid to a compound of Formula 1 in anorganic solvent; (q) cooling the reaction mixture obtained from Step(p), typically to room temperature, to form a precipitate; and (r)isolating the precipitate of Step (q). The organic solvent in Step (p)may be one or more selected from the group consisting of acetone,methylethylketone, ethyl acetate, acetonitrile, tetrahydrofuran,heptane, and C₁˜C₅ alcohol. For example, a mixed solvent of acetone andisopropyl alcohol may be used as the organic solvent. The ratio(volumetric ratio) of acetone and isopropyl alcohol in the mixed solventmay be in the range of 200˜280:100, preferably in the range of about250:100. The refluxing may be carried out at the temperature rangingfrom 50° C. to 120° C., preferably from 55° C. to 70° C.

In another aspect, the present invention provides a crystalline form Bof a hydrochloride of the compound of Formula 1, having an XRPD patternwith peaks at 7.3, 8.8, 11.8, 12.5, 13.2, 13.6, 14.5, 17.7, 18.6, 19.6,22.0, 24.9, 25.2, and 25.9° 2θ±0.2° 2θ.

Preferably, the crystalline form B of a hydrochloride of the compound ofFormula 1 may have the XRPD pattern of FIG. 2. And also, the crystallineform B of a hydrochloride of the compound of Formula 1 may have adifferential scanning calorimetry (DSC) thermogram showing anendothermic peak at between 229° C. and 235° C., preferably at 232±2° C.The onset temperature may be 230±2° C.

The present invention also includes, within its scope, a process forpreparing the crystalline form B of a hydrochloride of the compound ofFormula 1. Specifically, the present invention provides a process forpreparing the crystalline form B of a hydrochloride of the compound ofFormula 1, the process comprising exposing the crystalline form A of ahydrochloride of the compound of Formula 1 to a 40% or more relativehumidity condition so as to control the water contents thereof to about3.5% or more.

The present invention will be described in further detail with referenceto the following examples. These examples are for illustrative purposesonly and are not intended to limit the scope of the present invention.

Preparation Example 1: 1-(4-amino-3-nitrophenyl)guanidine hemicarbonate

A mixture of 4-amino-2-nitroaniline (100.0 g, 0.653 mol), purified water(200 mL), concentrated hydrochloric acid (61.2 g, 0.588 mol), andcyanamide (35.7 g, 0.849 mol) was stirred at 80-90° C. for 3 hours. Asolution of sodium carbonate (41.5 g, 0.392 mol) in purified water (500mL) was slowly added to the reaction mixture at about 65° C. Thereaction mixture was stirred for 2 hours, cooled to about 10° C., andthen filtered. The resulting solid was dried in vacuo to obtain 112.5 gof the titled compound. (Yield: 76.2%).

¹H-NMR (600 MHz, DMSO) δ 9.86 (br, 1H), 7.80 (s, 1H), 7.66 (s, 2H), 7.56(s, 2H), 7.29 (s, 1H), 7.15 (s, 1H)

Example 1: 2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-ol

A mixture of 1-(4-amino-3-nitrophenyl)guanidine hemicarbonate (110.0 g,0.486 mol), methyl 3-oxohexanoate (91.1 g, 0.632 mol), and n-butanol(330 mL) was stirred at 9° C. for 15 hours. The reaction mixture wascooled to room temperature and then filtered. The resulting solid wasdried under reduced pressure to obtain 111.3 g of the titled compound.(Yield: 79.1%, HPLC purity: 98.2%)

¹H-NMR (400 MHz, DMSO) δ 10.82 (br, 1H), 8.98 (br, 1H), 8.57 (s, 1H),7.49 (d, 1H), 7.30 (s, 2H), 7.02 (d, 1H), 5.62 (s, 1H), 2.35 (t, 2H),1.72-1.63 (m, 2H), 0.91 (t, 3H)

Example 2: 2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl4-methylbenzenesulfonate

To a solution of 2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-ol(106.5 g, 0.368 mol) and p-toluenesulfonyl chloride (64.27 g, 0.337 mol)in acetone (700 mL), was added triethylamine (37.2 g, 0.368 mol). Thereaction mixture was stirred at room temperature for 3 hours and thenfiltered. Toluene (1,065 ml) was added to the resulting filtrate, whichwas then concentrated to 430 ml so as to remove acetone. The resultingsolution was directly used in the preparation of the compound ofFormula 1. A portion of the solution was concentrated under reducedpressure for identification of the resulting product and the ¹H-NMRspectrum data obtained therefrom are as follows.

¹H-NMR (400 MHz, DMSO) δ 9.73 (s, 1H), 8.33 (br, 1H), 7.90 (d, 2H), 7.56(d, 1H), 7.43 (d, 2H), 7.32 (s, 2H), 6.96 (d, 1H), 6.44 (s, 1H), 2.59(t, 2H), 2.40 (s, 3H), 1.74-1.65 (m, 2H), 1.18 (t, 3H)

Example 3: 4-methylbenzenesulfonic Acid Salt of2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl4-methylbenzenesulfonate

To a solution of 2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-ol(20.0 g, 0.069 mol) and p-toluenesulfonyl chloride (14.5 g, 0.076 mol)in acetone (170 mL), was added triethylamine (8.4 g, 0.083 mol). Thereaction mixture was stirred at room temperature for 3 hours and thenfiltered. p-Toluenesulfonic acid (14.5 g, 0.076 mol) was added to theresulting filtrate. The mixture was stirred at room temperature for 2hours and then filtered. The resulting solid was dried under reducedpressure to obtain 37.9 g of the titled compound. (Yield: 89.1%)

¹H-NMR (400 MHz, CDCl₃) δ 11.70 (s, 1H), 8.31 (s, 1H), 7.81 (d, 2H),7.66 (d, 2H), 7.56 (d, 1H), 7.43 (d, 2H), 7.32 (s, 2H), 6.96 (d, 1H),6.44 (s, 1H), 2.59 (t, 2H), 2.40 (s, 3H), 1.74-1.65 (m, 2H), 1.18 (t,3H)

Example 4: 2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-ylmethanesulfonate

To a solution of 2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-ol(18.0 g, 0.062 mol) and methanesulfonyl chloride (7.8 g, 0.068 mol) inN,N-dimethylformamide (54 mL), was added triethylamine (7.6 g, 0.075mol). The reaction mixture was stirred at room temperature for 3 hours.Purified water (180 mL) and toluene (54 mL) were added to the reactionmixture, which was then filtered. The resulting solid was dried underreduced pressure to obtain 18.0 g of the titled compound. (Yield: 79.0%)

¹H-NMR (400 MHz, DMSO) δ 10.62 (br, 1H), 8.76 (br, 1H), 8.54 (s, 1H),7.48 (d, 1H), 7.31 (s, 2H), 6.99 (d, 1H), 5.66 (s, 1H), 3.72 (s, 3H),2.34 (t, 2H), 1.70-1.64 (m, 2H), 0.91 (t, 3H)

Example 5: 2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl4-bromobenzenesulfonate

To a solution of 2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-ol(10.0 g, 0.035 mol) and 4-bromobenzenesulfonyl chloride (9.7 g, 0.038mol) in N,N-dimethylformamide (30 mL), was added triethylamine (4.2 g,0.041 mol). The reaction mixture was stirred at room temperature for 3hours. Purified water (180 mL) and toluene (54 mL) were added thereto.The extracted organic layer was directly used in the preparation of thecompound of Formula 1. A portion of the organic layer was concentratedunder reduced pressure for identification of the resulting product andthe ¹H-NMR spectrum data obtained therefrom are as follows.

¹H-NMR (400 MHz, DMSO) δ 9.72 (s, 1H), 7.96 (br, 2H), 7.83 (d, 2H), 7.56(d, 1H), 7.27 (s, 2H), 6.98 (d, 1H), 6.47 (s, 1H), 2.59 (t, 2H),1.74-1.65 (m, 2H), 0.90 (t, 3H)

Example 6:(S)—N-(1-(2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl)pyrrolidin-3-yl)acetamide

To a mixture of tert-butyl (S)-3-acetamidopyrrolidine-1-carboxylate(70.0 g, 0.307 mol) and toluene (700 mL), was added p-toluenesulfonicacid monohydrate (116.7 g, 0.613 mol). The reaction mixture was stirredat room temperature for 6 hours. To the reaction mixture, were added asolution of 2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl4-methylbenzenesulfonate in toluene obtained in Example 2 anddiisopropylethylamine (198.1 g, 1.533 mol). The reaction mixture wasstirred at 80-90° C. for 5 hours and then concentrated under reducedpressure. To the resulting residue, were added methanol (210 mL) and a50% sodium bicarbonate solution (70 mL). The resulting mixture wasstirred at room temperature for 2 hours and then distilled water (1,050mL) was dropwise added thereto. After filtering the reaction mixture,the resulting solid was dried under reduced pressure to obtain 105.5 gof the titled compound. (Yield: 86.0%, HPLC purity: 99.1%)

¹H-NMR (400 MHz, DMSO) δ 8.99 (s, 2H), 8.17 (s, 1H), 7.58 (d, 1H), 7.16(s, 2H), 6.93 (d, 1H), 5.79 (s, 1H), 4.35 (m, 1H), 3.70-3.35 (m, 6H),2.40 (t, 2H), 1.82 (s, 3H), 1.71-1.65 (m, 2H), 0.92 (t, 3H)

Example 7:(S)—N-(1-(2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl)pyrrolidin-3-yl)acetamideHydrochloride (Crystalline Form A)

To a mixture of(S)—N-(1-(2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl)pyrrolidin-3-yl)acetamide(10.0 g, 0.025 mol), acetone (250 mL), and isopropyl alcohol (100 mL),was added concentrated hydrochloric acid (2.6 g, 0.025 mol) at 50° C.The reaction mixture was refluxed under stirring for 20 hours, cooled toroom temperature, and then filtered. The resulting solid was dried underreduced pressure at about 60° C. to obtain 9.8 g of the titled compound.(Yield: 90.0%, HPLC purity: 99.9%)

¹H-NMR (600 MHz) δ 8.56 (d, 1H), 7.37-7.34 (m, 1H), 6.96-6.93 (m, 1H),6.09 (d, 1H), 4.53-4.47 (d, 1H), 3.91-3.43 (m, 4H), 2.62-2.58 (m, 2H),2.36-2.28 (m, 1H), 2.12-2.05 (m, 1H), 1.98 (s, 3H), 1.78-1.74 (m, 2H),1.06-1.03 (t, 3H)

The resulting product was subject to X-ray powder diffraction (XRPD)analysis. The X-Ray powder diffraction (XRPD) patterns were collected ona Bruker D8 Advance diffractometer using Cu—Kα radiation (λ=1.5406 A)and operating at 40 kV and 40 mA. The patterns were collected byscanning 20 from 4 to 40 with increment of 0.02 and scan speed of 0.1second per step (divergence slit: 0.3 and antiscatter slit: 0.3). Theobtained XRPD spectrum is shown in FIG. 1, which shows characteristicpeaks at 7.4, 9.1, 12.0, 12.5, 13.5, 14.1, 15.9, 16.8, 18.3, 19.1, 24.6,25.3 and 26.8° 2θ±0.2° 2θ.

And also, the resulting product was subject to differential scanningcalorimetry (DSC) analysis. The differential scanning calorimetry (DSC)analysis was carried out with the Mettler Toledo DSC 1 STAR DifferentialScanning calorimeter. The analytical conditions thereof are as follows:sample was placed into an aluminum pan; the pan was covered with analuminum lid (pinhole); 99% purged nitrogen gas (gas flow rate: 50mL/min); start temperature 30° C.; end temperature 300° C.; and heatingrate 10° C./min. As a result thereof, the endothermic peak was observedat between 229° C. and 235° C. The onset temperature was 230.4° C. andthe maximum peak was observed at 233.0° C.

Example 8:(S)—N-(1-(2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl)pyrrolidin-3-yl)acetamideHydrochloride (Crystalline Form B)

The crystalline form A of(S)—N-(1-(2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl)pyrrolidin-3-yl)acetamide hydrochloride prepared in Example 7 was exposed in a wet chamberhaving 40% relative humidity, for 5 hours or more, to obtain the titledcompound.

¹H-NMR (600 MHz) δ 8.56 (d, 1H), 7.37-7.34 (m, 1H), 6.96-6.93 (m, 1H),6.09 (d, 1H), 4.53-4.47 (d, 1H), 3.91-3.43 (m, 4H), 2.62-2.58 (m, 2H),2.36-2.28 (m, 1H), 2.12-2.05 (m, 1H), 1.98 (s, 3H), 1.78-1.74 (m, 2H),1.06-1.03 (t, 3H)

The resulting product was subject to X-ray powder diffraction (XRPD)analysis and differential scanning calorimetry (DSC) analysis, accordingto the same methods as in Example 7. The obtained XRPD spectrum is shownin FIG. 2, which shows characteristic peaks at 7.3, 8.8, 11.8, 12.5,13.2, 13.6, 14.5, 17.7, 18.6, 19.6, 22.0, 24.9, 25.2, and 25.9° 2θ±0.2°2θ. As a result of the differential scanning calorimetry (DSC) analysis,the endothermic peak was observed at between 229° C. and 235° C. Theonset temperature was 229.4° C. and the maximum peak was observed at232.2° C.

Experimental Example 1: Stability Tests

(S)—N-(1-(2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl)pyrrolidin-3-yl)acetamide hydrochloride prepared according to WO 2012/115480 (Amorphousform, Test compound 1) and the crystalline form A of(S)—N-(1-(2-((4-amino-3-nitrophenyl)amino)-6-propylpyrimidin-4-yl)pyrrolidin-3-yl)acetamide hydrochloride prepared in Example 7 (Test compound 2) were storedunder the conditions of 60° C. and 75% RH for 2 weeks. The amounts ofeach test compound and the deacetylated impurities were analyzed withHPLC so as to measure the respective HPLC purities. The results thereofare shown in Table 1 below.

TABLE 1 HPLC purities Storage time Test compound Initial 1 week 2 weeksTest compound 1 Compound 98.7% 95.5% 86.6% (Amorphous form) Deacetylated0.58% 3.78% 12.7% impurities Test compound 2 Compound 99.6% 99.6% 99.6%(Crystalline form A) Deacetylated 0.08% 0.07% 0.07% impurities

As shown in Table 1 above, the crystalline form A according to thepresent invention exhibited not only high purity from the initial, butalso no significant change in the HPLC purity and the amount ofdeacetylated impurities under the conditions of 60° C. and 75% RH. Onthe contrary, the amorphous form according to the prior art exhibitednot only high level of deacetylated impurities from the initial, butalso marked decrease in the HPLC purity and the marked increase in theamount of deacetylated impurities under the conditions of 60° C. and 75%RH. Therefore, from the above results, it can be confirmed that thecrystalline form according to the present invention has excellentstability.

The invention claimed is:
 1. A process for preparing a compound ofFormula 1 or acid addition salt thereof, comprising (a) reacting acompound of Formula 2 or salt thereof with (S)-3-acetamidopyrrolidine toprepare a compound of Formula 1; and optionally (b) reacting thecompound of Formula 1 with an acid to prepare an acid addition salt ofthe compound of Formula 1:

wherein, R¹ is a C₁˜C₃ alkyl group; or a phenyl group optionallysubstituted with one or more substituents selected from the groupconsisting of halogen, C₁˜C₃ alkyl, and cyano.
 2. The process accordingto claim 1, wherein the reaction of a compound of Formula 2 or saltthereof with (S)-3-acetamidopyrrolidine is carried out in the presenceof a base.
 3. The process according to claim 2, wherein the base is oneor more selected from the group consisting of potassium tert-butoxide,sodium hydroxide, potassium hydroxide, sodium hydride, sodium carbonate,potassium carbonate, potassium phosphate, sodium phosphate,1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,4-diazabicyclo[2.2.2]octane(DABCO), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), pyridine,triethylamine, diisopropylamine, and diisopropylethylamine.
 4. Theprocess according to claim 1, wherein the acid used in Step (b) ishydrochloric acid.
 5. The process according to claim 1, wherein thecompound of Formula 2 or salt thereof is prepared or formed by a processcomprising (i) reacting a compound of Formula 5 or salt thereof withmethyl 3-oxohexanoate to prepare a compound of Formula 4; (ii) reactingthe compound of Formula 4 with R¹-sulfonyl halide, wherein R1 is thesame as defined in claim 1, to prepare a compound of Formula 2; andoptionally (iii) converting the compound of Formula 2 to a salt thereof:


6. The process according to claim 5, wherein the reaction of thecompound of Formula 4 with R¹-sulfonyl halide is carried out in thepresence of a base.
 7. The process according to claim 6, wherein thebase is one or more selected from the group consisting of potassiumtert-butoxide, sodium hydroxide, potassium hydroxide, sodium hydride,sodium carbonate, potassium carbonate, potassium phosphate, sodiumphosphate, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU),1,4-diazabicyclo[2.2.2]octane (DABCO), 1,5-diazabicyclo[4.3.0]non-5-ene(DBN), pyridine, triethylamine, diisopropylamine, anddiisopropylethylamine.
 8. The process according to claim 5, wherein thereaction mixture of Step (ii) is directly used in the reaction of Step(a), without isolating the compound of Formula 2 or salt thereof.
 9. Acompound of Formula 2 or salt thereof:

wherein, R¹ is the same as defined in claim 1.